The problem of constructing buildings such as homes which are well insulated is a long-standing one, although the demand for such construction has increased dramatically since the costs of energy for heating buildings and homes has increased significantly over the last decade or two. A major problem seems to be that structural materials having a high degree of rigidity and strength by their very nature are also quite dense and tend to be, for that reason, quite good conductors of heat. Consequently, when homes or other buildings are constructed of normal building materials, chosen because of their rigidity and strength, the heat from the home is readily radiated through such structural members and to the outside air. For that reason, materials having a higher R value tend to have less strength and more air spaces between the parts thereof.
One excellent insulating material is expanded polystyrene which can be formed in rigid blocks, but its application and wall structure is somewhat limited because it does not have the strength of wood or concrete or the like. Consequently, there is a need for methods of constructing walls and roofs of materials having a high insulating R value, while at the same time having the necessary strength and rigidity.